About

A free guide to starting plants from seed — native plants, prairie perennials, rock garden species, trees and shrubs — that tells you what to do to your seed and on what date to begin.

What it does

Seed packets and reference books describe germination in shorthand like 70L(90% in 10-14 d), and none of it tells you when to start. Here, each species' instructions are laid out as plain steps — what to do, for how long, at what temperature — and counted back from your last spring frost, so you get a start date for your own garden.

Look up a plant with the search box or the A–Z list, read its steps and start date, and put your whole season into the sowing planner.

New to growing from seed? Learn explains why seed needs stratifying, the kinds of seed and the plant words used here.

Who makes it

Deno’s Garden is built and kept up by one person, Amir Abed, a software engineer in Orange County, California. He started the site in 2026 and works on it on his own: the code, the data, the pictures and the email. If you find something wrong, or have a plant you’d like to see here, write to him.

Why one plant can have several protocols

A protocol is one recipe for getting a seed to sprout. Many plants here have several, because Deno sowed the same seed in different ways and wrote down what happened each time. Most often the difference is temperature: one batch kept at 70°F (a warm room), another at 40°F (a fridge), or one after the other, like a summer followed by a winter. Some seed sprouts only after a cold spell, some only in warmth, and some needs both, in the right order. Other protocols try soaking, nicking the seed coat, light or GA-3. Each is shown on its own, with its own result, so you can pick the one that suits you.

Where you live does not change the recipe. Deno's tests were done indoors at set temperatures, so they work the same anywhere. Your location changes only the calendar: dates are counted back from your last frost, so the same recipe starts later in Minnesota than in Georgia, where spring comes sooner. Two things can still differ. Seed sown outdoors keeps the weather's schedule, not a fixed one, and Deno's outdoor results come from his garden in Pennsylvania, so somewhere much warmer or colder it may be faster or slower. And seed from another source (a different wild population, or older seed) may not behave like the batch Deno tested.

Three rules it keeps

You can always see where a protocol came from.

Open "Show the original text" on any card to read the source's own words, exactly as published. If the steps on a card don't match that quotation, trust the quotation and let us know, so we can fix the card.

Nothing is averaged.

When a source describes more than one treatment, or two sources disagree, you see each one separately, with its own dates and its own citation, and you choose. A blended figure would be one nobody actually tested.

Nothing unchecked is shown as instructions.

Until a person has checked a record against its source, its page shows the quotation only — no steps, temperatures or dates — and is marked "not yet reviewed". All 1,644 species here have been checked. It is better to give you no date than a wrong one you might act on.

Confidence

Each protocol card carries one of two marks. Verified means a person read the original source and checked every step. Derived means the steps were read from the source by computer and then spot-checked by a person; the quotation on the card lets you check the rest yourself.

For how to carry out each step — cold, moist stratification, light, GA-3, hard seed coats — and how to grow the seedlings on, see How the steps are done, in Deno’s own words.

The name

Deno’s Garden is named for Norman C. Deno, whose Seed Germination Theory and Practice is the source of most of the protocols here. He placed that work in the public domain, which is why you can read his words on every card. He did not make this site, and it is not published by him or his estate; the name is a tribute, not a byline. Any mistakes on a card are ours, not his, and the quotation beside it shows you which is which.

Sources

Where a species page credits Deno’s Garden Records, it means the grower's notebook listed above — Deno’s Garden is Amir Abed, and observations made here are labeled as observations rather than dressed up as a citation. Everything else is quoted from a published source and named in full on the card that uses it.

Protocols are used under the licenses above. The site's own text and code are separate from the sources it quotes.

The Community page's From the plant world box is not part of any protocol. Its headlines are the publishers' own, from the science-news feeds of Phys.org, ScienceDaily and Mongabay, and link to their pages. Its new species come from IPNI, the International Plant Names Index, published on the Internet by the Royal Botanic Gardens, Kew, Harvard University Herbaria & Libraries and the Australian National Herbarium, under CC BY. Both are refreshed each night.

Where the dates come from

Each start date is worked out backwards from the day your seedlings can go outside. Two figures in that sum are estimates, so treat every date as a guide rather than a deadline:

• 28 days from germination to a seedling big enough to plant out. Sources rarely give this, so it is the same for every species.
• 21 days for the seed to germinate, used only when the source doesn't say. Where it does, the source's figure is used.

Your frost date comes from NOAA's 1991–2020 US Climate Normals, matched to your ZIP code using Census ZIP code areas (32,883 ZIP codes; a ZIP code that is not one of them, such as a PO box, uses the closest one that is). It is the median date: in half of years the last frost comes later. The planner tells you which weather station it used and how far away it is — worth checking if you live in hills, where elevation matters more than distance — and offers the later, one-year-in-ten date if you would rather play it safe. Species pages without a ZIP code use a national average of May 3, which will be wrong for most places, so put in your own when you can.

What this is not

It is a guide to what published sources say, not a promise. Seed varies with its age, where it came from and how it was stored, and the same treatment can give different results from one year to the next. Treat each date as the middle of a range, and sow more seed than you think you need.

Reading every species page is free and needs no account. A free account adds two plant identifications. The sowing planner is free for everyone for now. The paid plan adds My Garden, unlimited identification and no ads; visitors and free accounts see ads. See the Privacy Policy for what an account stores.

Something wrong?

Please tell us. These reports help most:

• A card whose steps don't match its own quotation. That is our mistake, and we fix those first.
• A protocol you think is wrong in the source itself, ideally with a reference for a better one.
• A plant that isn't here yet. Requests decide which species are added next.

Every record is checked by a person before it is published, so changes you suggest are read and confirmed by hand rather than appearing on the site straight away.